Fibrin sealants, and glues, are well known and are used extensively in various clinical settings. Such sealants are indicated as adjuncts to hemostasis in surgeries when control of bleeding by conventional surgical techniques, including suture, ligature, and cautery is ineffective or impractical. In these cases, the sealant was applied topically. Delivery devices have been developed for these uses. Typical fibrin sealant devices are adapted to spray the fibrin sealant.
More recently, fibrin sealant has been used to treat degenerative disc disease that leads to discogenic pain. In this regard, U.S. Pat. No. 6,468,527 (Austin) discloses the injection of a fibrin sealant into the intra-discal space. This patent discloses use of a dual syringe system wherein thrombin and fibrinogen initially mix in a Y-connector that attaches to a needle and to the two syringes. The fibrin sealant immediately begins clotting upon contact of the fibrinogen and the thrombin. The components continue to mix and clot as they travel down the spinal needle toward the tip of the needle that is in the disc.
However, the inventors herein have recognized that the prior delivery device shown in U.S. Pat. No. 6,468,527 is prone to clogging due to clotting of the components within the needle. In addition, the inventors have recognized that it would be desirable for a surgeon administering the sealant to know the pressure of the components being delivered so that the surgeon does not over-pressurize the disc and/or so that the surgeon can use the delivery device as a diagnostic tool to ascertain the extent of damage to the disc.